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From: Christoph Hellwig <hch@lst.de>
To: Damien Le Moal <dlemoal@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>,
	Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.de>,
	Joe Breuer <linux-kernel@jmbreuer.net>,
	Bart Van Assche <bvanassche@acm.org>,
	Bagas Sanjaya <bagasdotme@gmail.com>, Pavel Machek <pavel@ucw.cz>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Len Brown <len.brown@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Kees Cook <keescook@chromium.org>,
	Tony Luck <tony.luck@intel.com>,
	"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
	Thorsten Leemhuis <linux@leemhuis.info>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Phillip Potter <phil@philpotter.co.uk>,
	Linux Power Management <linux-pm@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux Hardening <linux-hardening@vger.kernel.org>,
	Linux Regressions <regressions@lists.linux.dev>,
	Linux SCSI <linux-scsi@vger.kernel.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Hannes Reinecke <hare@suse.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Martin Kepplinger <martin.kepplinger@puri.sm>,
	Kai-Heng Feng <kai.heng.feng@canonical.com>
Subject: Re: Fwd: Waking up from resume locks up on sr device
Date: Thu, 15 Jun 2023 06:40:15 +0200	[thread overview]
Message-ID: <20230615044015.GA4720@lst.de> (raw)
In-Reply-To: <41b069c7-8723-4507-3e5a-1d1878db9002@kernel.org>

On Thu, Jun 15, 2023 at 09:10:28AM +0900, Damien Le Moal wrote:
> > Here's what commit e27829dc92e5 ("scsi: serialize ->rescan against 
> > ->remove", written by Christoph Hellwig) says:
> > 
> >     Lock the device embedded in the scsi_device to protect against
> >     concurrent calls to ->remove.
> > 
> > That's the commit which added the device_lock() call.
> 
> Thanks for the information.
> 
> +Christoph
> 
> Why is adding the device_lock() needed ? We could just do a
> scsi_device_get()+scsi_device_put() to serialize against remove. No ?

No.  scsi_device_get just increments a reference count, and thus
prevents ->release from beeing called.  ->remove is not in any way
affected by the refcount.

  reply	other threads:[~2023-06-15  4:40 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-09 11:04 Fwd: Waking up from resume locks up on sr device Bagas Sanjaya
2023-06-10  6:38 ` Bagas Sanjaya
2023-06-10  8:55   ` Pavel Machek
2023-06-10 13:27     ` Bagas Sanjaya
2023-06-10 15:03       ` Bart Van Assche
2023-06-11  9:05         ` Joe Breuer
2023-06-11 11:31           ` Bagas Sanjaya
2023-06-14  4:49           ` Damien Le Moal
2023-06-14  5:37             ` Kai-Heng Feng
2023-06-14  6:31               ` Damien Le Moal
2023-06-14  7:22               ` Damien Le Moal
2023-06-14  6:57             ` Hannes Reinecke
2023-06-14  7:35               ` Damien Le Moal
2023-06-14 14:26                 ` Alan Stern
2023-06-14 14:40                   ` Rafael J. Wysocki
2023-06-14 18:04                   ` Bart Van Assche
2023-06-14 22:44                     ` Damien Le Moal
2023-06-15  0:10                   ` Damien Le Moal
2023-06-15  4:40                     ` Christoph Hellwig [this message]
2023-06-15  4:57                       ` Damien Le Moal
2023-06-15  5:09                         ` Christoph Hellwig
2023-06-12  3:09         ` Damien Le Moal
2023-06-12  6:09           ` Hannes Reinecke
2023-06-12  7:22             ` Damien Le Moal
2023-06-12  7:36               ` Kai-Heng Feng
2023-06-12  7:47                 ` Damien Le Moal
2023-06-12 14:33                   ` Alan Stern
2023-06-12 15:37                     ` Rafael J. Wysocki

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